1. Field of the Invention
The present invention relates to a radio antenna arrangement for radio communications with two way radio communication systems. The two way communications are in the decimeter (UHF) and/or centimeter (SHF) wave lengths, with an antenna element serving as the signal emitter, mounted on the outside of the motor vehicle near the upper edge of a slanted windshield. The emitting antenna is secured on a vehicle body with a base plate mounted on the roof or the windshield, or partly covering the line of separation between the roof and windshield.
2. The Prior Art
Radio antennas similar to this type are known, for example from WO 93/23890, as well as in the form of group antennas in German Patent DE 43 39 162.
These prior art antennas are frequently mounted either on the roof of the vehicle, on the rear window, or on the upper edge of the windshield. In special cases, the antenna can be mounted directly within the separation zone between the upper edge of the windshield and the roof as described in German Patent DE 43 39 162 (FIG. 6).
One of the problems created by these antennas includes finding a way to provide the signal input. There are two problems that can occur in providing the signal input. Firstly, when the antenna is mounted on the windshield, the input signal can be provided using capacitively acting coupling elements in the windshield. Secondly, when it is mounted within the zone of the roof, the input signal has to be fed through a hole provided in the roof, which is undesirable in terms of vehicle construction.
Another problem is that with modern radio systems is that communications with a number of radio communication services frequently have to take place simultaneously. Examples of radio telephone services are the GSM-system (D-network) and the mobile radio telephone system E-network, as well as the AMPS-system used in the USA, which operate in the 800 to 1900 MHz band. In addition to cellular telephone service, satellite radio communication service is also possible, such as, through the Global Positioning System (GPS), or a bidirectional satellite ("Leos"), which is currently in the planning stage, or with a receiving antenna for terrestrial or direct digital audio broadcasting signals in the L-band. All of these services operate in the 1400 to 1600 MHz band.
It is known from previous experience that separately mounting a number of antennas on the vehicle is not widely accepted, so that there is demand for a combination antenna that can receive a number of radio communication services.